When Liu Daozhen was young, he often went fishing in Cao Ze. He is good at whistling, and everyone who hears him lingers. An old woman, knowing that he was not an ordinary person, liked his whistle very much and killed a pig for him to eat. Daozhen finished eating the pig and didn't thank him at all. Seeing that he was not full, the old woman sent another pig. Liu Daozhen ate half of it and returned the rest to the old woman. Later, he served as the official minister, and the old lady's son was a junior official, so Daozhen surpassed him and appointed him. Your history doesn't know the reason, so he asked his mother, and she told him what happened. So he took beef and wine to visit Daozhen. Tao Zhen said, "Let's go, let's go! I have nothing to repay you. "